Many buildings are required by code to have fire suppression sprinkler systems. Further, residential structures are increasingly being provided with fire suppression systems. CPVC piping systems are ideally suited for fire sprinkler system applications because of their resistance to corrosion, the lightness of material, ease of installation, and other desirable properties.
Under current standards, in-line coupling of abutting CPVC pipe sections is accomplished by use of solvent cement techniques to form a permanent bond therebetween. Such techniques require sufficient time for the solvent cement to cure. Furthermore, at times it may become necessary to make modifications or repairs to existing CPVC fire sprinkler systems. The use of solvent cement demands that the modification to the pipe network be accomplished in a generally dry environment.
In use, fire sprinkler systems are often under continuous water pressure. In prior systems, for a system modification or repair, the targeted sprinkler section must be removed from service and drained. The new CPVC pipe sections must be connected into the system adhered by solvent cement which requires an applicable cure time. Thereafter, the system is brought back online and tested. During this process, which may extend over 24 hours or longer, at least a portion of the fire sprinkler system is out of service, requiring an alternate fire watch. Thus, there exists a need to provide a method to join CPVC piping which eliminates the down time associated with prior joining processes.
Use of the solvent cement creates an irreversible pipe connection. Thus, misalignment or other adverse conditions cannot be readily corrected. Further, some piping systems, such as piping used in some food preparation systems, require frequent disassembly for cleaning. Thus, there exists a need in the art for a CPVC piping system that joins pipe segments in a releasable manner.
Other piping systems such as those using metal pipes or plastic material such as PVC, may utilize mechanical couplings with grooved or rolled pipes. Some mechanical couplings employ an annular resilient sealing member to engage the closely abutting pipe ends. Commonly, the sealing members are formed of elastomeric compositions employing plasticizers or other agents. Lubricants are also commonly applied for ease of installation. However, such prior techniques cannot readily be transferred for use with CPVC piping. The CPVC piping may have compatibility issues with the plasticizers or lubricants which could cause stress cracks in the pipe material.
In PVC piping, a method of grooving the pipe near the cut end is called “rolled grooving”. In rolled grooving, material is pressed inwardly to form a circumferential depression on the outer surface. The displaced material in this process effectively reduces the inner diameter of the pipe. The reduced inner diameter affects fluid flow. Also, the character and properties of CPVC does not readily lend itself to a rolled grooving process.
In some other grooving processes, pipe wall material is removed by a blade or other cutting implement. For example, grooving metal conduits may be accomplished with a cutting tool. However, the prevalent teaching with respect to CPVC piping is that CPVC should not be grooved. CPVC fire sprinkler systems have to meet stringent UL and other standards. Because wall thickness is decreased during a cutting or grooving process, grooving CPVC pipe has been discouraged to prevent weakening of the pipe wall. Thus, prior pipe system processing and sealing methods are not readily adapted to CPVC piping systems. There exists a need for methods and testing procedures for a system employing grooved CPVC piping including a seal compatibility protocol.
Further, mechanical couplings often rely on compression forces to provide a sealing engagement between the pipes and the sealing member. The compression force applied to CPVC pipe must not exceed predetermined limits. Thus, to employ mechanical compression-type fittings with CPVC systems, there exists a need for a compression limiting mechanism.
Other desired configurations or modifications of a CPVC pipe network may include branched connections from a first pipe line to a perpendicular pipe line. In the art, a cut-in to an existing CPVC fire sprinkler system is made by shutting down the system and draining. An appropriate socket style tee fitting is used in combination with socket unions, grooved coupling adapters, and flanges. The fitting is adhered to the cut pipe ends using solvent cement. Care must be taken to follow cut-in cure schedules for the solvent cement. Similar to in-line coupling, the process requires considerable down time of the sprinkler system as well as an alternate fire watch method. Thus, there exists a need in the art for cut-in fittings and procedures that significantly reduce downtime of the sprinkler system, while still providing a system that meets stringent fire protection standards.
If mechanical couplings and fittings are to be used with CPVC pipe systems, such items must be utilized in ways that accommodate the properties of the CPVC piping. Compression and support requirements of the CPVC material must be met. Thus, there exists a need for mechanical fixtures that are compatible with the properties of CPVC piping.
Also, as discussed above, mechanical fittings have a major drawback in that elastomeric sealing members are often made of compositions comprising plasticizers and other agents that can degrade or impair performance of CPVC piping. Thus, there exists a need to provide a compatibility protocol with the use of mechanical fittings with CPVC piping.
Further, certain fire testing standards have been developed that are specific to plastic piping systems. Incorporation of mechanical fittings and adapters into such systems requires that the hybrid system meet certain performance standards. Thus, there exists a need for a plastic/mechanical system to perform in accordance with accepted fire standards. Also, introduction of resilient members to a plastic system requires that the CPVC pipe be subjected to new criteria of performance related to environmental stress crack resistance.
There exists a need for methods and devices for providing grooved CPVC piping. Further, there exists a need in the art for an apparatus operative to provide precise drilling of CPVC pipe for direct cut-in.
Fire sprinkler systems often use vertical risers to feed branches of the distribution system. Often, metallic pipe is used for the risers that feed into the fire sprinkler system. The problem is that CPVC cannot be used in riser applications due to the need for adequate support of CPVC piping without excessive compression of the material. Until now, the maximum diameter CPVC pipe used in fire sprinkler systems is about 2″. Thus, there exists a need for larger pipe diameters (up to 4″) with a clamping mechanism to allow the use of greater diameter pipes as the vertical risers.